Maintenance Tips???

Hi I'm new here just picked up my 02 ranger a day ago. I know buying from a private seller you get alot of surprises when it comes to buying used vehicles. But this truck is running absolute sound. Everything seems to be in decent working condition i can't complain. Just a question. What gas should i run in it? And also what are some quick preventive maintenance procedures i can do to make sure im rolling steady for a while, i do not mind getting under the truck or hood at all. Need a good Checklisit of every thing you can think of. Thanks

All 3 are designed to run 87 octane, regular gas
If you will be pulling or hauling a load I would put some 91 or 93 octane in, the 2.3l and 4.0l have Knock sensors, so they can run 87 octane, but that does reduce power when pulling a load, so up to you, does NOT hurt anything.
87 octane and 93 octane have the same power per gallon, so one is not "better" than the other, octane is a heat rating, engine will run hotter when pulling a load, so in the case of the 2.3l or 4.0l the higher octane helps these engine run better spark timing

Need to know engine type to suggest other maintenance
Also manual or automatic?

All 3 are designed to run 87 octane, regular gas
If you will be pulling or hauling a load I would put some 91 or 93 octane in, the 2.3l and 4.0l have Knock sensors, so they can run 87 octane, but that does reduce power when pulling a load, so up to you, does NOT hurt anything.
87 octane and 93 octane have the same power per gallon, so one is not "better" than the other, octane is a heat rating, engine will run hotter when pulling a load, so in the case of the 2.3l or 4.0l the higher octane helps these engine run better spark timing

Need to know engine type to suggest other maintenance
Also manual or automatic?

On my 3.0 I didn't watch/flush the coolant enough. Rust/etc. shortened the life of the water pumps/engine. So... flush and new coolant regular is probably a good tip :) Nice truck, sometimes I wish I had the extended cab...

!!!!!!!!!!!! The engine light is not on when the key turns. **** i got scammed!!!!! Just when i felt like i checked everything I DIDNT! So now im about to get the truck read and install a new bulb 😞 but i do have hope for the truck aestectically its 8/10. It cranks every time 1st try. No leaks that ive seen. No weird knocks. All the gears work, all my levels are reading as they should. Heat and air work fine and vehicle still functions and drives smooth. it accelerates normally. Im really praying it's something minor because i need this truck for work Im thinking the guy hid the light to get it sold asap but c'mon bro that was a scum move, karma hits hard though.

Check fuse #11 in cab fuse box, 7.5amp, thats the power for the CEL(check engine light), also for a few gauges in the dash, so its probably OK but check it
Then in the engine bay, the computer is located in upper firewall just off center to passenger side, larger 104 pin connector

Pin #2 on that connector is a Pink/light green stripe wire, thats the Ground for the CEL, computer grounds that pin with key on, if you have a test light you can hook it up to 12volt(battery) and to that pin/wire, then turn on the key, test light should light up

If fuse #11 is OK and computer Grounds pin 2 then yes bulb in dash is burned out or disabled, in either case it isn't a good sign, burned out means it was ON a long long time, and disabled.......well that speaks for itself, lol.

Check fuse #11 in cab fuse box, 7.5amp, thats the power for the CEL(check engine light), also for a few gauges in the dash, so its probably OK but check it
Then in the engine bay, the computer is located in upper firewall just off center to passenger side, larger 104 pin connector

Pin #2 on that connector is a Pink/light green stripe wire, thats the Ground for the CEL, computer grounds that pin with key on, if you have a test light you can hook it up to 12volt(battery) and to that pin/wire, then turn on the key, test light should light up

If fuse #11 is OK and computer Grounds pin 2 then yes bulb in dash is burned out or disabled, in either case it isn't a good sign, burned out means it was ON a long long time, and disabled.......well that speaks for itself, lol.

that's exactly what i checked yesterday! Put a new bulb in turned the ignition on the check engine light flashed on cranked the car on it turned off was so relieved took it to my shop to get it read before i get an inspection everything checked out, but later yesterday i ran into another issue i think i myself caused from being under the hood messiging with the battery unplugging and replugging it to configure my dash lights. The problem now or was that my overhead light would not turn off with all doors closed and lights off. What was weird is that the light would switch off when i drive it a ways down, but as soon as i came to a stop and took the key back out the ignition the light would beem no matter if i had the door on or not so at that point i think i had short circuited something while working in the dash frustrated i took my truck to my uncle he was messing with it with the battery on i insisted he unplug the battery before messing with the dome light sure enuf he tries to take of the lamp and boom there goes the dome light and the little cabin back lights/3rd tail lights the clear ones and the brake light. idk too much about lights on these trucks but wtf is going on. Like a day after i got the truck my glove box light wouldn't shut off either. It's like one you fix one thing another thing just mysteriously goes bad. And the truck is a 4.0 automatic v6

1995 and up Rangers got a Body Computer, from 1995 to 2003 it was the GEM(generic electric module), 2004 to 2012 its was the SJB(smart junction box)

The GEM controls all cab electrics, i.e. when you turn on the wipers, that switch is connected to the GEM, NOT the wipers, GEM gets the change in the switch position and IT turns on the wipers
Same for interior lights, when you open a door GEM gets the "door open" signal from the door switch, it then turns on the Dome Light, so no direct connection to most cab electrics

When a door is open you should have a "Door Ajar" light on the dash, if you don't then that bulb may also be burned out, if that's the case then a door switch may be Grounded(switch shows Ground to GEM when door is OPEN)
So a shorted switch wire or a bad switch would cause GEM to leave dome light on because it still "thinks" door is open
If "door ajar" light is not working then that would be my guess.

There is also a Dash light dimmer control that by passes GEM and turns on Dome light directly, it could be shorted and is keeping Dome light powered no matter what.

Rangers, 1995 and up, also have a Battery Saver Relay, GEM controls this with a timer circuit, relay is closed with key on, or Doors unlocked(keyless entry) or opened
After key off and no electrical activity, the GEM timer will count down for 20-30minutes, then OPEN the battery saver relay, which cuts power to all interior lights and exterior lights as well, except brake lights, GEM power is also cut, but only partially, the Keyless entry module and door switches are still monitored.